HFC cable system with wideband communications pathway and coax domain nodes

ABSTRACT

System and method to extend the data carrying capacity of a hybrid fiber cable (HFC) network by adding wideband RF signal capability above 1 GHz, and replacing at least some CATV active devices such as amplifiers with a new type of Coax Domain Node (CDN) device that acts to segment the CATV cable portion of the HFC network into a series of smaller domains. The CDN generally filter RF signals from 5-865 MHz, while amplifying and passing RF signals over 1 GHz. Upstream capability is enhanced because the CDN intercept 5-42 MHz upstream signals from each domain and convert to 1 GHz+ signals. Downstream capability is also enhanced because the CDN can take efficiently encoded 1 GHz+ digital data, QAM modulate it, and locally inject into each domain without crosstalk between domains. The system pushes data management and downstream from the head end to the CDN, creating more throughput.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent applicationSer. No. 12/907,970, “HFC CABLE SYSTEM WITH SHADOW FIBER AND COAX FIBERTERMINALS”, filed Oct. 19, 2010; U.S. patent application Ser. No.12/907,970 in turn claimed the priority benefit of U.S. provisionalapplication 61/385,125 “IMPROVED HYBRID FIBER CABLE SYSTEM AND METHOD”,filed Sep. 21, 2010, inventor Shlomo Rakib; and U.S. patent applicationSer. No. 12/692,582, “DISTRIBUTED CABLE MODEM TERMINATION SYSTEM” filedJan. 22, 2010, inventor Shlomo Rakib; this application is also acontinuation in part of U.S. patent application Ser. No. 12/692,582,“DISTRIBUTED CABLE MODEM TERMINATION SYSTEM” filed Jan. 22, 2010,inventor Shlomo Rakib; the contents of these applications areincorporated herein by reference.

FIELD OF THE INVENTION

The invention is in the general field of Cable Television and HybridFiber Cable systems, particularly with regard to providing extendedfeatures and Internet access.

BACKGROUND OF THE INVENTION

Cable television (CATV), originally introduced in the late 1940's as away to transmit television signals by coaxial cables to houses in areasof poor reception, has over the years been modified and extended toenable the cable medium to transport a growing number of different typesof digital data, including both digital television and broadbandInternet data.

Over the years, this 1940's and 1950's era system has been extended toprovide more and more functionality. In recent years, the CATV systemhas been extended by the use of optical fibers to handle much of theload of transmitting data from the many different CATV cables handlinglocal neighborhoods, and the cable head or operator of the system. Herethe data will often be transmitted for long distances using opticalfiber, and the optical (usually infrared light) signals then transformedto the radiofrequency (RF) signals used to communicate over CATV cable(usually in the 5 MHz to about 865 MHz frequencies) by many localoptical fiber nodes. Such systems are often referred to as hybrid fibercable systems, or HFC systems. The complex electronics that are used bythe cable operator to inject signals (e.g. data) into the system, aswell as extract signals (e.g. data) from the system are often referredto as Cable Modem Termination Systems or CMTS systems.

In a typical HFC system, at the various optical fiber nodes, the opticalfiber signals are transformed back into RF signals and are then carriedby the various neighborhood CATV coax cables to various households.Unlike fiber, which can carry optical signals for extensive distanceswithout significant signal strength attenuation, the RF signalsattenuate fairly rapidly as a function of distance over the CATV coaxcables. This attenuation versus distance function increases as thefrequency of the RF signals increases. For example, using RG-59 cable,at 10 MHz, the RF signal attenuation versus distance is about 1.1 dB/100feet, at 100 MHz, the RF signal attenuation versus distance is about 3.4dB/100 feet, at 400 MHz, the attenuation rate is 7.0 dB/100 feet, and at1000 MHz (1 GHz), the attenuation rate is 12 dB/100 feet. Other types ofcoax cables, such as RG-6 cables, have lower attenuation versus distancecharacteristics, but the same sort of attenuation problem still exists.

Thus, in order to maintain the RF signal of the various upstream anddownstream signals while traveling over neighborhood CATV coax cables,neighborhood CATV systems typically employ various active (powered)devices, such as powered forward and reverse (bidirectional) RFamplifiers and the like. At present, using CATV systems that often havea maximum frequency of about 550 or 850 MHz, these active devices areoften spaced about every 1000 feet.

Each active device can have several (e.g. 1-4) neighborhood CATVsub-cables connected to it, and often to maintain RF power over cabledistances of several thousand feet, more than one (usually 1-3) activedevices can be connected along a single stretch of coax cable. As aresult, at a neighborhood level, the coax cable wiring pattern of CATVsystems often has a “tree” like structure, where the branches of theCATV coaxial cable tree spring off of the various active devices. Thefirst or main CATV coax cable that connects to the RF signal originatingfrom the optical fiber node is often referred to as the “trunk” cable,and the various coax cables that split off of the trunk cable are oftenreferred to as branch cables, and the branch cables in turn can haveother branch cables splitting off of them as well. As the various trunkand branch cables cover the local neighborhood, and generally situatedin between the various active devices, various taps, splitters, anddrops on the neighborhood or “trunk” CATV cable connect varioushouseholds to the CATV cable. In order to provide power for the variousactive devices, often the CATV coax cable system will carry electricalpower as well. As might be expected, the process of negotiatingeasements and right of way to route the neighborhood CATV cables isburdensome, however this process has been going on for over 50 years invarious parts of the country, and by now is well established.

At present, in United States CATV systems, the 5-42 MHz frequency regionis reserved for upstream communications back from the various cablemodems to the cable plant/cable head end, and the majority of thebandwidth, typically in the 54-547+ MHz range (often the upper endextends to 865 MHz and beyond) is reserved for downstream communicationsfrom the cable plant to the various households. European CATV systemsfollow a slightly different scheme where the upstream communicationsfrequencies extend up to the 65 MHz region, and the downstreamcommunications frequencies are typically in the 88 to about 865 MHzrange. The intermediate frequencies between 42-54 MHz (US) and 65-88 MHz(Europe) are generally unused due to the filtering switch over in thisregion. Due to rapid signal attenuation, the higher frequencies aboveabout 750 to 865 MHz (here referred to generically as 1 GHz+ frequenciesor wideband frequencies) are seldom used at present.

A more detailed discussion of prior art in this field can be found incopending application Ser. Nos. 12/692,582, and 12/907,970, the contentsof which are incorporated herein by reference. Prior art work withvarious types of CMTS systems and fiber nodes includes Liva et. al.,U.S. Pat. No. 7,149,223; Sucharczuk et. al. US patent application2007/0189770; and Amit, U.S. Pat. No. 7,197,045.

Although at present, the CATV spectrum above approximately 1 GHz isgenerally unused, there has been some interest by Xtend Networks Ltd,Tel-Aviv Israel, and other companies (e.g. Javelin Innovations, Inc.) invarious methods to utilize this wideband spectrum. This prior art work,exemplified by U.S. Pat. Nos. 7,138,886; 7,209,497; 7,616,890;7,748,023; 7,904,932; 7,933,772; and 7,927,739 has generally tended tofocus on addressing various issues related to frequency conversion ofsignals between the spectrum under 1 GHz, and suitable taps andamplifiers to handle the spectrum above 1 GHz, but generally haveotherwise tended to deal with the CATV spectrum above 1 GHz as if thishigher frequency region should be considered to be a simple extension ofpresent CATV data communications practices.

BRIEF SUMMARY OF THE INVENTION

The invention is based, in part, on the insight that although the CATVfrequencies above 1 GHz do indeed represent a presently untapped CATVdata transmission opportunity, more efficient use of these 1 GHzfrequencies may be obtained by more substantially departing from pastCATV data communications practices.

The invention is also based, in part, on the insight that the CATV RFspectrum above 1 GHz may be usefully viewed as almost being its ownseparate communications pathway, to be managed in a way that that can bequite different from the traditional or legacy management of the CATV RFspectrum below 1 GHz.

Data is primarily transmitted over CATV cable in the form of variousradio-frequency (RF) Quadrature Amplitude Modulated (QAM) channels.Prior art practice in the CATV industry has usually been to generatethese QAM channels at the cable head end, transmit them through opticalfiber (capable of transmitting enormous amounts of data) as QAMmodulated optical signal, to various optical fiber nodes connected tolocal CATV cables, where data is then transmitted by various RFwaveforms. As previously discussed, these local CATV cables in turn areusually arranged in a tree-like network with various cable branches, allultimately connecting to various user CATV cable connected communicationdevices (communications devices), such as cable modems, set top boxes(STB), Ethernet terminals, and the like, distributed throughout thevarious neighborhoods.

From a data carrying standpoint, the optical fiber cable can be viewedas a huge (i.e. very high capacity) data pipeline, terminating at thevarious optical fiber nodes into various tiny data straws (e.g. muchless data carrying capacity) carried by RF signals over CATV cable.

Although extending the frequency of CATV cable from, for example, theprior art 0-1 GHz range by providing perhaps additional data carryingcapability in the 1-2 or 1-3 GHz bandwidth region will, of course,improve the data carrying capability of the local CATV cable by perhapsa factor of 2-3, if prior art methods of carrying data are used, the neteffect will not otherwise be overly dramatic. That is, instead of themassive optical fiber data pipe terminating in various single tiny datastraws (that represent the local optical fiber nodes and the datacarrying capability of the various local CATV tree and branch networks),we will now terminate in two or perhaps three tiny local data straws.

Thus an important invention insight is that unless a substantiallydifferent CATV data management scheme is adopted for extended highfrequency 1-2 or 2-3 GHz range CATV signals, the improvements will notbe all that dramatic. That is, any improvement upgrade of CATVcomponents from the present roughly 0-1 GHz range to perhaps andextended 0-2 or 0-3 GHz+ range will not be all that great, and perhapsmay not be worth the effort. The data straws will still be tiny,relative much more substantial data carrying capability of the opticalfiber data pipeline.

The invention is also based on the insight that various individual users(represented by local communication devices) connected to the massiveoptical fiber data pipe by the tiny data straw of their local CATV cablesystem do not generally need to use very much of the optical fiber datapipe carrying capability. Rather, what the local, CATV connected, usersneed is an ability to rapidly pick and choose portions of the data ofinterest from the massive optical fiber data pipe. If the various userscan quickly get a customized narrowcast version of their data selection,their data selection may adequately fit down the tiny data straw oftheir local CATV cable. Similarly, even when local users may on occasionneed to quickly upload massive amounts of data, they still will not needto use much of the data carrying capability of the massive optical fiberdata pipeline. Rather, if the various local CATV users can overcome thebottleneck of the limited upstream capability of prior art CATV cable,their upstream needs will likely also be met for the foreseeable future.

The invention is based, in part, on the insight that it is desirable todepart from past practices, which relegated much of the process ofoptical fiber and CATV signal data management and signal conversion atthe cable head end. Rather, according to the invention, improvedperformance can be obtained by pushing much more of the system's datamanagement and signal conversion capability much closer to the end user,in fact almost as close to the end user as commercially feasible. Thusthe present disclosure continues the work of prior disclosures Ser. Nos.12/907,970 and 12/692,582, which also taught the benefits of pushingmore of the systems data management and signal conversion capabilitycloser to the end user.

The invention is also based, in part, on the insight that CATVfrequencies above 1 GHz represent a great opportunity to implement suchan improved downstream-pushed data management signal and conversioncapability. Thus, for example, a local user communication device (e.g. acable modem, STB, or Ethernet terminal), upon needing extra upstream ordownstream data channels, may initiate a request for extra service (e.g.more data carrying capability) to a new type of CATV active device, herecalled a “Cable Domain Node”. The Cable Doman Node (CDN) in turn canrelay this request for extra service to the local cable fiber node, andthe local cable fiber node can in turn access the massive optical fiberdata pipe. The local cable fiber node can transmit and receive data fromthe optical fiber, and relay it to the local Cable Domain Nodesdistributed along the CATV cable, often using the 1 GHz+ frequencyrange.

In some embodiments, this extra service may be transmitted using moreefficient digital protocols (e.g. using various Ethernet protocols),between the various Cable Domain Nodes, or between the Cable DomainNodes and the local optical fiber node, often in the 1 GHz+ (greaterthan 1 GHz) frequency range, and then converted to and from various RFQAM signals for sending to local CATV users. Depending on theimplementation desired, these RF QAM signals can either be in thestandard 0-1 GHz range, in the wideband 1-2, 1-3, or 1-3+ GHz range, orboth the standard range and the wideband range.

In some embodiments, particularly useful when high backwardcompatibility is desired, as well as other applications, it may beuseful to configure the invention's Coax Domain Nodes to suppress orfilter some or all of the CATV signals below 1 GHz, while continuing topass all CATV signals above 1 GHz. This type of embodiment has the neteffect of segregating a stretch of CATV cable with multiple Coax DomainNodes into individual domains that exist in the coax cable in-betweeneach set of Coax Domain Nodes. Within each coax cable domain (domain),CATV signals below 1 GHz can continue to flow freely between the coaxcable connected households, but these CATV signals below 1 GHz may notflow freely past the Coax Domain Junction to the coax cable bounded bythe next set of Coax Domain Nodes. By contrast, the Coax Domain Nodesmay be configured to allow the CATV RF signals above 1 GHz to flowfreely up and down the CATV cable across multiple Coax Doman Nodes.

Thus, in some embodiments, the invention may be a system and method toextend the data carrying capacity of a hybrid fiber cable (HFC) networkby adding wideband RF signal capability above 1 GHz, and replacing atleast some CATV active devices such as amplifiers with a new type ofCoax Domain Node (CDN) device that acts to segment the CATV cableportion of the HFC network into a series of smaller domains. The CDNgenerally filter or terminate RF signals from 5-865 MHz, whileamplifying and relaying or passing RF signals over 1 GHz. Using thisscheme, the system's upstream capability is greatly enhanced (e.g. by anorder of magnitude or more), even with legacy communications devices,because the CDN can intercept 5-42 MHz upstream signals from each domainand convert to 1 GHz+ signals, thus relieving upstream signal congestionand contention. Downstream capability is also greatly enhanced becausethe CDN can take efficiently encoded 1 GHz+ digital data, QAM modulateit, and locally inject into each individual coax domain as needed by thelocal communications devices, without worry of unwanted crosstalkbetween domains. The invention thus pushes data management anddownstream from the cable head end to the various Cable Domain Nodes,creating more upstream and downstream throughput.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an overall view of the various frequencies and datachannels that are presently allocated for a typical CATV cable systemscarrying legacy analog television FDM channels, QAM digital televisionchannels, and various types of Data Over Cable Service InterfaceSpecification (DOCSIS) data, as well as the wideband frequencies aboveabout 1 GHz.

FIG. 2 shows an overall view of the various wavelengths allocated forprior art optical fiber wavelength division multiplexing schemes, ascompared to alternative dense wavelength division multiplexing (DWDM)methods, which in some embodiments of the invention may be used by thewideband (1 GHz+) communications pathway network to carry upstream ordownstream data.

FIG. 3 shows a simplified version of how prior art HFC systems cantransmit data from the cable plant or cable head to different opticalfiber nodes, each usually connected to a tree and branch like structureof CATV coax cables. The coax cables often contain multiple activedevices (e.g. RF amplifiers) often spaced roughly every thousand feet tocorrect for signal attenuation.

FIG. 4 shows how the invention's “wideband communications pathway” whileusing the same CATV cable as the prior art neighborhood CATV cable treeand branch coax cables, operates. According to the invention, thiswideband communications pathway interacts with a new type of “CoaxDomain Node” device (CDN). These CDN devices will often replace priorart CATV active devices such as amplifiers. The CDN devices may removesome or all of the 5-42 MHz upstream RF signals traveling back from thevarious households along the particular CATV branch cable or trunk cableserviced by that particular CDN device. The CDN devices then cantransform at least some of the upstream CATV RF signals and data intoupstream 1 GHz+ frequency signals and data, and transmit this back tothe optical fiber node and then to the cable head, thus relievingupstream congestion on the neighborhood CATV cables.

FIG. 5A shows a block diagram showing various embodiments of the CoaxDomain Node device, and the optical fiber node that serves this type ofdevice.

FIG. 5B shows a block diagram that focuses on a second alternativeembodiment of the optical fiber node (CDN-fiber node) and one scheme inwhich this optical fiber node can interact with the cable head end.

FIG. 5C shows a block diagram that focuses on a third alternativeembodiment of the optical fiber node (CDN-fiber node) and an alternativescheme in which this optical fiber node can interact with the cable headend.

FIG. 5D shows a block diagram that focuses on a fourth alternativeembodiment of the optical fiber node (CDN-fiber node) and an alternativescheme in which this optical fiber node can interact with the cable headend.

FIG. 6 shows an overview of how, in some embodiments of the invention,Mini-slot Allocation Packet (MAP) data may be used to analyze andextract the digital data encoded by the upstream signals. The upstreamdigital data may then be sent back to the cable head and the Cable ModemTermination System (CMTS) at the cable head using a more efficientdigital protocol, such as a GigE protocol, first along the 1 GHz+wideband communications pathway, and then after the optical fiber nodealong the HFC optical fiber. Once at the fiber node, this upstream datacan either be sent at a different wavelength from the downstream opticalfiber signal, or alternatively can be sent back along a differentoptical fiber. At the cable head CMTS end as desired, the same MAP datamay be used, in conjunction with the digital data, to reconstitute theoriginal upstream CATV RF signal, and this in turn may be fed into alegacy CMTS.

FIG. 7 shows one type of wideband communications pathway and Coax DomainNode addressing scheme. Here either each Coax Domain Node, or in someembodiments related groups of Coax Domain Nodes may be partitioned intodifferent domains, and the communications devices (e.g. cable modems andother devices) served by their respective Coax Domain Node can beaddressed by the cable plant or head end CMTS accordingly. In one simplescheme, the household communications devices falling within each CoaxDomain Node domain may be handled by the CMTS as if they were simplysmall independent neighborhoods, thus partitioning what is really alarger CATV coax neighborhood into multiple virtual smallerneighborhoods. This scheme helps preserve backward compatibility withlegacy CMTS and CMTS software.

FIG. 8 shows one scheme in which the Coax Domain Nodes may allocatefrequency and payloads among the various coax cable domains.

FIG. 9 shows a detail of one scheme in which the Coax Domain Nodes mayallocate upstream frequencies and payloads among the various coax cabledomains. Note that in this scheme, because the different domains areisolated from each other in the downstream frequency region (e.g. 5-42MHz or 5-88 MHz), these frequency and time slices need not be consistentbetween the different domains, even though the domains all fall atvarious locations along the same neighborhood CATV cable.

FIG. 10 shows a schematic of how the cable head end can, with the aid ofa suitable router, take various forms of data in IP space, such asanalog video, digital video, video on demand, as well as other signalsgenerated by the head end cable modem termination system (CMTS),modulate this to analog optical signals, add various types of narrowcastpayloads (in digital format), multiplex these, and transmit as variousoptical signals over the optical fiber to various optical fiber nodes.

FIG. 11 shows an alternative scheme of how the cable head end can, withthe aid of a suitable router, take various forms of data in IP space,such as analog video, digital video, video on demand, as well as othersignals generated by the head end cable modem termination system (CMTS),modulate this to analog optical signals, add various types of narrowcastpayloads (in digital format), multiplex these, and transmit as variousoptical signals over the optical fiber to various optical fiber nodes.In this alternative scheme, the narrowcast signals (narrowcast payload)can be sent using presently unused optical fibers (e.g. dark fiber).

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, the invention may be a system and method forenhancing data carrying capacity of a hybrid fiber cable (HFC) networkwith a cable head end, at least one optical fiber, at least one opticalfiber node terminating on at least one CATV coaxial cable, (CATV cable).This CATV cable will often be connected to a plurality of other branchCATV cables thus forming a CATV Tree and Branch Network. Usually aplurality of various types of communication devices (e.g. set top boxes,cable modems, Ethernet terminals, etc.) will be connected to this CATVTree and Branch Network at various places.

Although standard (e.g. prior art optical fiber nodes) or slightlymodified prior art optical fiber nodes may often be used for theinvention, in a preferred embodiment, the optical fiber node itself willhave some unique capabilities, such as the ability to carry out variousCoax Doman Node functions to be described.

The invention relies on sending both non-standard CATV RF signals of 1GHz and greater, and more conventional CATV RF signals between about5-865 MHz, over various CATV cable pathways. Unfortunately standard(prior art) CATV coax cable is often populated with various devices(e.g. filters, amplifiers, taps) that can block 1 GHz+ RF signals. Thusa first step for the invention's system or method is to create a coaxcable based bidirectional wideband communications pathway mediated by RFfrequencies of approximately 1 GHz or greater between the CATV opticalfiber node(s) and to and between a plurality of Coax Domain Nodesdisposed along the CATV Tree and Branch network. This can generally bedone by picking coaxial cable that has good 1 GHz+ frequencytransmission characteristics, and also using filters, amplifiers, andtaps that can conduct both low frequency (less than 1 GHz) and highfrequency (greater than 1 GHz) RF signals. For example, by swapping outearlier, non 1 GHz+ compliant filters, amplifiers, and taps withimproved 1 GH+ compliant filters, amplifiers, and taps, a legacy CATVcable system can be upgraded to at least handle the 1 GHz+ signalsrequired for the invention.

Further, according to the invention, at various junctions along the CATVtree and branch network, a new type of active device, here called a CoaxDomain Node, will be placed. These Coax Domain Nodes (CDN) will bedescribed in more detail later in this discussion. Briefly, the CoaxDomain Nodes act to relatively freely pass (e.g. relay, boost, or relayand boost with some modifications to be described) CATV RF signals ofapproximately 1 GHz frequency or more. However the Coax Domain Nodeswill often be configured to intercept and terminate most or all priorart CATV RF signals, such as both upstream and downstream signals in theroughly 5 MHz range to about 865 MHz (nominal upper end of prior artCATV RF signals), here described as CATV RF signals of approximately 1GHz frequency or less.

Although it might thus look, at first glance, like a prior art 5-865 MHzcapable CATV communication device, such as a set top box or cable modemconnected to CATV cable with periodic Coax Domain Nodes, might thus becompletely unable to either transmit or receive any signals to and fromthe head end or the optical fiber node end of the CATV cable, this isnot the case, because the invention essentially acts to push some of theRF signal generating and receiving properties of the cable head end downto the level of the individual Coax Domain Nodes. This is because thevarious Coax Domain Nodes designed to be capable of communicating withtheir own set of local CATV cable connected communications devices on alocal domain specific basis.

Here, for simplicity, consider a “domain” to be a stretch of CATV coaxcable that is terminated on either end by either two Coax Domain Nodes,a optical fiber node and one Coax Domain Node, or a Coax domain node andan a RF terminator end cap. Absent active assistance by the Coax DomainNodes, the CATV coax cable in this domain is thus isolated in theroughly 5-865 MHz RF region from the other sections of CATV coax cable,but RF signals of 1 GHz+ can still pass through the domain (activelyassisted or modified by the Coax Domain Nodes as needed).

The Coax Domain Nodes (CDN) work by performing various RF signalmodifying processes. In particular, they act to intercept local upstreamCATV RF signals from various communications devices connected to thedomain (stretch of coax cable) served by that particular CDN. Aspreviously discussed, these local upstream CATV RF signals willgenerally have a frequency of approximately 1 GHz or less, often 5-42MHz in the US, or 5-54 MHz in Europe. The CDN will terminate at leastsome (and often all) of these local upstream CATV RF signals, and aspreviously discussed will often terminate some or all of the standardCATV upstream channels (e.g. 65-about 865 MHz in the US, 88 to about 865MHz in Europe) as well. Here for simplicity, we will generally assumethat all signals below about 1 GHz (e.g. 5-865 MHz or so) are usuallyblocked, but of course various notch filters, active devices, and thelike can be designed to allow certain intermediate frequencies less than1 GHz to pass by or be relayed by the CDN without departing from thespirit of the invention.

The CDN intercept the local upstream signals, remodulate and oftenreformat them to the 1 GHz+ frequency range, and then allow the localupstream channels to pass from one domain to another, and on down to theoptical fiber node and ultimately the cable head.

The methods by which the CDN do this by modulating of these localupstream CATV RF signals (or alternatively some or all of the dataobtained from these local upstream CATV RF signals) to an RF frequencyof approximately 1 GHz or more will be described later in thisspecification.

Using this procedure, the invention's system and method can then use thewideband (1 GHz+) capable CATV cable network to transport upstream databack to the optical fiber node and to the head end (e.g. “backhaul”) aseither a frequency shifted (and often repackaged) version of the localupstream CATV RF signals themselves. Alternatively the underlying datafrom these local upstream CATV RF signals can be extracted, repackaged,and frequency shifted. By either mechanism, the system sends theupstream data back, using 1 GHz+ RF signals to the optical fiber node.The optical fiber node can in turn transmit the upstream signals back tothe head end using optical fiber at various wavelengths (to bediscussed).

The various Coax Domain Nodes can also locally generate downstream RFsignals for the various (and otherwise RF isolated) cable communicationsdevices, such as legacy 5-865 MHz capable communications devices. (Notethat more sophisticated next-generation cable communications devicesmight access the 1 GHz+ RF frequencies directly). To do this, the CoaxDomain Nodes can selectively extract data carried by the 1 GHz+ widebandRF signals down the wideband communications pathway, modulate this datainto downstream CATV RF signals of approximately 1 GHz or less (oftenusing the prior art CATV channels in the 54-865 US MHz range or European88-865 MHz range as desired), and transmit this now domain specificdownstream data to the various CATV cable connected communicationsdevices on their particular domains (stretch of CATV cable).

This method can thus be quite backward compatible with prior art CATVsystems, while also providing much additional functionality. Inparticular the invention's methods can handle upstream CATV signal suchas DOCSIS, DVB, Aloha, and other non-DOCSIS signals. Indeed, there is noreason to restrict the upstream frequencies to their prior art 5-42 MHz(US) or 5-54 MHz (Europe) limits. When less backward compatibility isdesired, upstream signals up to 1 GHz could be intercepted andbackhauled in this manner. As will be discussed in more detail later,the Coax Domain Nodes can handle the upstream RF signals by variousmethods. One method is to simply sample and digitize at least some ofthe upstream CATV RF signals, for example by Nuquist sampling methods at2× the highest frequency of the particular upstream RF signals sampled.This digitized data can then be used to modulate a higher frequency (1GHz+) RF signal, which will then be relatively freely transported backto the fiber node and head end.

Alternatively, as previously mentioned, more sophisticated methods maybe used. For example, instead of simply sampling the full CATV upstreamRF signal, the underlying data carried by this upstream RF signal can beextracted locally (e.g. at the Coax Domain Node), and then repackagedinto a much more concise or condensed 1 GHz+ RF signal for subsequentbackhauling to the fiber node and head end. To do this, however, theCoax Domain Nodes will need to be able to locally read and interpret theupstream data, and to do this they will need access to the various CATVdata encoding and decoding schemes, which are often provided byMini-slot Allocation Packet (MAP) data.

As an example of a more sophisticated method, the process of digitizingthe upstream CATV RF signals can be done by obtaining (usually from thecable head end) Mini-slot Allocation Packet (MAP) data for at least someof said upstream CATV RF signals, and using this Mini-slot AllocationPacket (MAP) data to demodulate and extract at least some of the thisupstream digital information. Once this is done, the extracted upstreamdata can then be reformatted into an alternative (and usually morebandwidth efficient) format for 1 GHz+ frequency RF transmission back tothe fiber node, and from there to the cable head end.

One advantage of using this type of MAP decoding method is that thismethod is used and understood by prior art CATV systems and legacy headend equipment. Thus this method can be generally compatible with legacyhead end equipment, because once the data is received at the head end,the same Mini-slot Allocation Packet (MAP) data can be used tosubsequently remodulate or reproduce the original digital informationcarried by the upstream signals into reconstituted upstream CATV RFsignals at the cable head. This produces reconstituted upstream CATV RFsignals. These reconstituted upstream CATV RF signals then be fed toeither a legacy Cable Modem Termination System, or an upgraded form of aCable Modem Termination system.

Because the 1 GHz+ wideband communications pathway taught here is new,there is no need to constrain its communication protocols to followlegacy CATV communications protocols. In principle a large variety ofdifferent 1 GHz+ RF communications methods may be used. For example,either the upstream or downstream wideband communication pathway datacan be transmitted, as per the design of the Coax Domain Nodes,according to a Time Division Duplex (TDD) scheme, Frequency DivisionDuplex (FDD) scheme, or Full Bidirectional Duplex without time orfrequency division scheme. Other schemes are also possible.

Because the invention's method will potentially be carrying much moreupstream and downstream traffic than was previously possible with priorart methods, in some embodiments, once this traffic reaches the variousoptical fiber nodes, it may be useful to use additional optical fiberwavelengths to carry this additional upstream or downstream datatraffic. Thus for example, the downstream data can be transmitted overthe optical fiber from said Cable head end to the optical fiber node ata first wavelength, and the upstream data can be transmitted from theoptical fiber node to the head end over the optical fiber at one or morealternate (second, third) wavelength(s).

In order to transmit data downstream on the frequencies below about 1GHz, because the Coax Domain nodes will normally terminate these signalsfrom the prior section of cable, the Coax Domain Nodes must thus beconfigured to locally modulate and transmit such signals (e.g. 65-865MHz signals for the US, 88-865 MHz signals for Europe). Although inprinciple any RF modulation scheme may be used for this, in view of theextensive use of QAM modulation methods in the CATV industry, and thehuge investment in legacy QAM capable cable devices, in a preferredembodiment, the various Coax Domain Nodes will be equipped with at leastone, and often a plurality of, QAM modulators for downstream datatransmission to the various communications devices.

In particular, in a preferred embodiment, at least some (and often all)of the various Coax Domain Nodes will contain at least one QAM modulatordevice capable of encoding, on a domain specific basis, selectedportions of the 1 GHz+ downstream wideband communications pathway datainto various RF QAM waveforms (usually in the 65/88 to around 865 MHzregion). These QAM modulators will (in conjunction with a deviceconfigured to select the appropriate portion of the 1 GHz+ widebandsignal to transmit), modulate at least selected portions of thedownstream wideband communications pathway data into downstream CATV RFsignals of approximately 1 GHz frequency or less.

Although in principle, the various Coax Domain Nodes may be fixedfunction “dumb” devices that continually perform the same operations, ina preferred embodiment, the Coax Domain Nodes (and usually theassociated CDN-fiber nodes) will be configured to be intelligent devicesthat can differentially add and extract data from the 1 GHz+ widebandcommunications pathway, and can transmit and receive on differentfrequencies according to various commands sent from a remote location,such as the cable head, the local communications devices, or even otherCoax Domain Nodes. To do this, the Coax Domain nodes will generally beconfigured with at least one microprocessor/microcontroller, appropriatesoftware, and appropriate ability to intercept commands (often sent onthe 1 GHz+ RF frequency range, or lower frequencies if the commands arebeing sent from local communications devices)

Thus the various Coax Domain Nodes will often comprise at least one QAMmodulator device capable of encoding selected portions of the digitallyencoded wideband communications pathway data into RF QAM waveforms ofapproximately 1 GHz frequency or less. The Coax Domain Nodes will alsooften have at least one software controllable switch that can beremotely directed to select, on a domain addressable basis, at leastsome of said digitally encoded Wideband communications pathway data. Theswitch can direct the QAM modulator device(s) to encode the selecteddigitally encoded ultrahigh frequency (1 GHz+) CATV RF communicationsdata into RF QAM waveforms of approximately 1 GHz frequency or less(e.g. the 65/88-865 MHz frequency region) at a selected set offrequencies within each said domain.

The Coax Domain Nodes will also usually have at least one remotelysoftware controllable RF packet processor that is capable of detectingupstream data carried by CATV RF upstream signals waveforms ofapproximately 1 GHz frequency or less (often in the 5-42/54 MHzfrequency region) generated by the local communications device(s) withineach domain. This RF packet processor can be configured to digitallyrepackage this upstream data (e.g. into a different format as needed)and retransmit this upstream data along the wideband communicationspathway in the form of 1 GHz+ RF signals.

As previously discussed, ideally this at least one software controllableswitch and/or said software controllable RF packet processor may bedesigned to be remotely configured by software to assign or reassign, ona domain specific basis, the frequencies used by this QAM rebroadcastdata.

FIG. 1 shows an overall view of the various frequencies and datachannels presently allocated for CATV (100). Typically the lowerfrequencies, such as 5-42 MHz (US) or 5-65 MHz (Europe), are allocatedfor use in transmitting data “upstream” from the individual cable modemsback to the Cable Head or Cable plant (102). Typically upstream data istransmitted using a time-share TDMA (Time Division Multiple Access)manner in which MAP data is sent to individual cable modems whichallocates certain times on roughly 2 MHz wide QAM channels to transmitdata. Starting at around 54 MHz on up to roughly 547 MHz, space waspreviously allocated for legacy analog video channels (104), whichtransmit on roughly 6 MHz wide FDM channels. At frequencies above that,frequencies (space, bandwidth) is currently allocated for digitaltelevision transmitting on roughly 6 MHz wide QAM channels (106), andabove that, space is currently allocated for DOCSIS services (108) thatmay transmit voice, on-demand video, IP, and other information, againgenerally as a series of 6 MHz wide QAM channels.

As previously discussed, the invention's wideband communications pathwaywill generally use the cable bandwidth above about 1 GHz, which isseldom used at present (109).

CATV cable (at least below about 850 to 865 MHz) thus has a finitebandwidth of at most about 100-200 QAM channels. When this bandwidth isused to serve a large amount of different customized types of data to alarge amount of different subscribers, this bandwidth quickly becomesexhausted.

A drawing showing how the CATV spectrum allocation can be described in amore simplified diagram is shown below (110), (120). The “upstream”segment (112) is an abstraction of all upstream channels, including bothpresently used upstream channels in the 5-42 MHz region, as well aspresent and future higher frequency upstream DOCSIS channels. The“video” segment (114) is an abstraction of both the now obsolete analogTV FDM channels, as well as the standard “digital video” channels, aswell as the projected digital video channels that will occupy the soonto be reclaimed analog bandwidths once the analog channels are phasedout. Segment (114) also represents other standard digital radio and FMchannels, and in general may represent any standardized set ofdownstream channels that will usually not be customized betweendifferent sets of users and neighborhoods.

The “DOC1” channel (116) may be (depending upon mode of use) either afull set or subset of present DOCSIS channels. wideband communicationspathway (118), as previously discussed, is in the higher frequency rangeof the CATV spectrum, such as the 1 GHz plus region, where various newGTTH (Gigabyte to the home) services may be provided using the widebandcommunications pathway network and the various Coax Domain Node devices.

FIG. 2 shows an overall view of the various optical wavelengthsallocated for both prior art optical fiber wavelength divisionmultiplexing schemes, and in some embodiments for various widebandcommunications pathway upstream and downstream data according to theinvention. Here the optical fiber will be used to carry information fromthe cable head end to the cable fiber node. According to the presentinvention, after the cable fiber node, information is then carried alongthe CATV cable as standard (e.g. less than 1 GHz) RF signals, andWideband (1 GHz+) RF signals.

Here the optical fiber wavelengths being used at present (150) include a1310 nm O-band wavelength (152) often used to transmit the various CATVRF channels, such as the various QAM channels, modulated essentiallyaccording to the same CATV RF waveforms, but at optical wavelengthsaccording to scheme (120). Supplemental data is often transmitted in theC-band around 1550 nm (154), often on optical wavelengths that, becausethey are modulated according to non-optimal CATV waveforms, must beseparated from each other by a relatively large wavelength separation,and which carry sub-optimal amounts of data per wavelength.

Depending upon the particular embodiment, at the fiber node, thewideband communications pathway network may transmit upstream data, orbackhaul data, according to either prior art methods, or alternativelyaccording to various multiple wavelength or Dense Wavelength DivisionMultiplexing methods (160). For example, in one simple embodiment, afterthe various Coax Domain Nodes in a neighborhood transmit theirparticular upstream data by 1 GHz+ RF signals over the widebandcommunications pathway, at the optical fiber node, the upstream data canthen be demodulated, analyzed, and repackaged and retransmitted,possibly using one or more of these different wavelengths.

Note that, as previously discussed, each neighborhood will generallyhave its own wideband communications pathway network, so that in thisscheme, different wideband communications pathway frequencies and timingwindows may often be reused between neighborhoods without problems ofinterference.

Here again, a legacy O-band analog signal may be used for upstreamcommunications as desired. Alternatively, multiple wavelengths of moreefficiently modulated data signals (such as one of the various opticalfiber GigE protocols) may be sent, often as a series of closely spacedwavelengths (162).

FIG. 3 shows a simplified version of how prior art HFC systems (200)transmit data from the cable plant or cable head end (202) to differentoptical fiber nodes (204), each usually composed of a tree like trunk(226) and branch (227) structure of CATV cables (226) with activedevices, such as RF amplifiers (229), often every thousand feet or so.Each neighborhood will typically consist of up to several hundred or afew thousand different houses, apartments, offices or stores (208) (herereferred to generically as “houses”), each equipped with their own cablemodems (not shown) and connecting to the CATV cable via a tap (231)Here, for simplicity, only the downstream portion of the HFC system isshown.

The cable head end will obtain standardized media content (210) (such asa standard assortment of analog and digital video channels) from one setof sources, and also obtain more individualized data (212), such asvideo on demand, IP from the Internet, and other individualized datafrom other sources. This data is compiled into a large number ofdifferent QAM (and at present also FDM) modulated CATV broadcastchannels at the CMTS shelf (214). This CMTS (214) will often have anumber of different blade-like line cards (216). These line cardstransmit the signals by optical fibers (218) to different areas (groupsof neighborhoods).

As previously discussed, typical HFC networks actually have a rathercomplex topology, which here is greatly simplified. Rather than sendingone optical fiber from the CMTS to each different neighborhood,typically optical fibers will serve multiple neighborhoods. To do this,the signal from the CMTS side optical fiber (218) will at least usuallybe split by an optical fiber splitter (not shown) into several differentoptical sub-fibers, and each sub-fiber in turn will in turn carry thesignal to different fiber optic nodes. Here only one Fiber Node, FiberNode 1 (204) is shown in order to better show the trunk and branch coaxcable structure of the neighborhood CATV cable system.

At a fiber node, such as FN 1 (204), the optical signal is convertedinto a CATV radio frequency (RF) signal and sent via CATV cables (226)to individual cable modems at individual houses (208) in eachneighborhood. Typically each neighborhood will consist of between 25 toa few thousand households, served by a CATV cable tree and branch likesystem of connected cables and active devices such as RF amplifiers(226), (227), and (229) that in turn connects to the local fiber node(204).

The CATV RF spectrum of this prior art HFC system is shown as (250).Here, as previously discussed, at least in the US, the 5-42 MHzfrequency region is reserved for upstream signals (252) such as upstreamDOCSIS signals (US DOCSIS) going from the households (208) to the cablehead (such as the CMTS (214), and the 54-865 MHz frequency region (254)is reserved for downstream signals, such as downstream DOCSIS (DSDOCSIS) going from the cable head to the households (208). Here the USDOCSIS region (252) is drawn as fairly dark (congested with dots) tosymbolize the high upstream congestion that occurs when an entireneighborhood of households attempts to send upstream data on thisrelatively limited region of CATV cable spectrum.

FIG. 4 shows how the invention's “wideband communications pathway”,symbolized by the dashed line (270), which runs at 1 GH+ frequencies(255) along exactly the same cable as the neighborhood CATV cable trunkand branches that carry the CATV signals from 5 to 865 MHz. (226),(227). This wideband communications pathway runs on CATV coax cablewhich in turn passes through various Coax Domain Nodes (272). Note howthe dashed lines from the 1 GHz+ wideband communications pathway areshown passing through the Coax Domain Nodes, while the darker solid line(226, 227) symbolizing 5-865 MHz (e.g. less than 1 GHz) are shown asbeing terminated at the various Coax Domain Nodes as a reminder of thesignal handling features of the Coax Domain Nodes.

In FIG. 4 and subsequent figures, the portion of the CATV cable facingthe optical fiber node and the head end of the cable will generally bedesignated as (226 u) and (270 u), and the portion of the CATV cablefacing away from the optical fiber node, and away from the head end ofthe cable will generally be designated as (226 d) and (270 d). Hereagain, (226) represents the CATV RF signals under about 1 GHz, while 270represents the CATV RF signals above about 1 GHz.

When a legacy section of CATV cable is upgraded, these Coax Domain Nodesmay often be positioned to replace legacy CATV active devices (e.g. RFamplifiers 229). These legacy active devices (229) are thus shown indotted lines to indicate that they may be replaced.

The Coax Domain Nodes are often configured to remove some or all of theupstream RF signals (e.g. 5-42 MHz signals) traveling back from thevarious households (208) along the particular CATV branch cable (227) ortrunk cable (226) serviced by that particular active device (229), butare often configured to freely pass the 1 GHz+ frequency RF signals.Thus FIG. 4 (as well as FIGS. 7 and 8) show the low frequency portion ofthe coax cable (226, 227) stopping at each Coax Domain Node (272), whilethe 1 GHz+ wideband frequencies (270) are shown as passing through eachCoax Domain Node (272).

The Coax Domain Nodes (272) will often transform the 5-42 MHz upstreamCATV RF signals and data into 1 GHz+ upstream RF signals and data, andthis can be carried back to the cable head, often by way of modifiedoptical nodes (205) via the HFC system.

In some embodiments, these modified optical nodes, alternatively calledCDN-fiber nodes, or CDN-FN (205) can, at least in part, be based onconcepts first discussed in the CMRTS or D-CMRTS optical nodes asdescribed in copending application Ser. No. 12/692,582 and/orprovisional application 61/385,125; the contents of both areincorporated herein by reference.

According to the invention, either prior art optical nodes may be used,and additional CDN devices may be added to intercept upstream data fromthe wideband communications pathway network (270) and repackage this fortransmission back to the cable head, often along optical fiber route(218), often using alternate fibers or alternate wavelengths.Alternatively, the optical node may be modified into a modified opticalnode with additional CDN functionality (205) with additional componentsto handle this repackaging internally.

In some embodiments, at the cable head, often just before the CMTS, adecoder apparatus (400) may intercept the optical fiber signals (218)and decode them into a form that can then be recognized by the CMTS. Forexample, such decoding may be used interpret the CDN domain informationinto a form that the CMTS can process, and may, for example, make eachdifferent Coax Domain Node domain appear to the CMTS as if it is aseparate CATV neighborhood. The decoder apparatus may also, in someembodiments, reconstitute upstream data signals coming from the CoaxDomain Nodes by way of MAP data or other methods. This will be discussedshortly.

In contrast to the CATV spectrum diagram (250) shown in FIG. 3, the CATVspectrum diagram (251) shown in FIG. 4 is slightly different. Inparticular, because much or all of the upstream traffic is now going byway of the Wideband communications pathway line (270), the upstreambandwidth (252), such as might be used to carry upstream DOCSIS (USDOCSIS) is much less congested, and is thus shown without the densepattern of dots to symbolize this difference. By contrast, thedownstream DOCSIS (DS DOCSIS) (245) bandwidth can remain much the sameas before. However, as is discussed elsewhere in this specification, thevery high frequency region, such as the 1 GHz+ region (255), will oftenbe used by the wideband communications pathway (270) and Coax DomainNodes (272) to deliver high bandwidth services, such as GigE to the home(GTTH), extended data channels, and other services.

FIG. 5A shows a block diagram of some of the major components in oneembodiment of the Coax Domain Node (272), as well as a diagram of someof the major components in a CDN-fiber node (205) that connects the CATVcable portion of the system (226, 227) with the optical fiber (218)going to the cable head end (e.g. 400, 216, 214, 202).

The CDN-fiber node (205), which may be used in some embodiments of theinvention, receives multiplexed data from the cable head end (e.g. 400,216, 214, 202) over optical fiber (218), often over one or morewavelengths (e.g. λ1, λ2, and so on). This multiplexed data can consistof various data streams, including for example a digitized analogpayload (e.g. head-end created QAM channels) often useful for legacycable purposes, and data for more specialized DOSIS services such asdata, voice, or video over IP.

This particular CDN-fiber node (205) is different from prior art fibernodes in that it also acts like a terminal Coax Domain Node, and canitself have Coax Domain Node functionality, as well as optical fibernode functionality. As previously discussed, this extra Coax Domain Nodefunctionality is optional. Thus for example, a more standard opticalfiber node may also be used if this optical fiber node simply upconvertsits signals to 1 GHz+ and then promptly feeds into a Coax Domain Nodewithout any intervening communications devices. Although the CDN-fibernode (205) example will generally be used in this discussion, theoptional nature of the added Coax Domain Node functionality should berecognized, and the invention is not intended to be limited to onlyCDN-fiber nodes. Any type of fiber node (optical fiber node) may, inprinciple, be used.

At the CDN-fiber node (205), a de-multiplexer (510) can convert thisoptically transmitted data (from different optical fiber wavelengths λas needed) into various RF transmitted data for both lower frequency RFtransmission (e.g. 5-865 MHz, often by way of RF signal synthesizer(514) and for wideband (1 GHz+) transmission over CATV coax cable (226,227), often by way of transceiver (512). The major components of theCDN-fiber node will comprise the demultiplexer (510), a transceivercapable of receiving and converting between the RF format and theoptical format (512) in the 1 GHz+ wideband range, a RF signalsynthesizer (514) that can take suitable optical data and repackage itfor lower frequency (e.g. 54-865 MHz) cable transmission, along thechain of Coax Domain Nodes, and a processor that can take local upstreamdata (often provided by households between the CDN-fiber node and thefirst true Coax Domain Node) sent on the 5-42 MHz frequency band) andrepackage it for optical transmission (516).

The <1 GHz RF signal synthesizer (514) provides downstream Coax DomainNode functionality to the CDN-fiber node (205). This RF signalsynthesizer (514) frequently produces RF signals in roughly the54/65-865 MHz range, and these can pass through Triplex unit (518 b) andonto the cable. These units (514)/(518) thus provide RF downstreamsignals in the 54-865 MHz range (US) or the 88-865 MHz range (forEurope) for any local communications devices (e.g. FIG. 4, 209)connected to the CATV coax cable in between the CDN-fiber node (205) andthe first true Coax Domain Node (272). In many embodiments, the <1 GHzRF signal synthesizer (514) may have at least one QAM modulator toconvert incoming data, often transmitted or modulated by an alternativeprotocol, into various downstream RF QAM waveforms with frequenciesunder 1 GHz (e.g. often in the 55-865 MHz range in the US), as will beshown in more detail in FIG. 8. Alternatively, the RF signal synthesizer(514) may more directly convert optically modulated QAM waveforms intodownstream signals by simpler O/A (optical to analog) converters. TheO/A methods and QAM modulation methods are not mutually exclusive, and amix of these methods may also be used.

Both the CDN-fiber node and the Coax Domain Nodes (CDN) will often haveone or more triplex signal splitting and frequency filtering unit (518,530, 532) that can both combine input data at various frequencies andpass these along to the CATV cable (226, 227), and also receive data(e.g. repackaged upstream data from the various Coax Domain Nodes thatis being carried upstream at 1 GHz+ frequencies) and send this upstreamdata to processor (516) for subsequent reformatting (as needed) andconversion to one or more suitable optical wavelengths suitable fortransmission on optical fiber (218). For example, Triplex unit (518) mayhave one part (518 a) that selectively removes (filters out) RFfrequencies below approximately 1 GHz, (i.e. the non-wideband signals),and passes the 1 GHz+ signals to and from the transceiver (512). Triplexunit (518) may have a second part (518 b) that selectively removes(filters out) the RF frequencies above the top end of the standard CATVrange, (e.g. removes frequencies above about 865 MHz), and also mayselectively remove (filter out) the normal CATV upstream frequenciesfrom about 5-42 MHz (in the US) or 5-65 MHz (Europe), and which onlyfreely passes the normal CATV downstream frequencies from about 54-865MHz (US) or 88-865 MHz (Europe). Triplex unit (518) may also have athird part (518 c) that filters out all RF signals above about 42 MHz(in the US) or 65 MHz (in Europe), and only allows the upstream RFfrequencies of about 5-42 MHz (in the US) or 5-54 MHz (in Europe) topass freely. Note that the other triplex units (530) and (532) will alsoact in this manner as well.

Thus processor (516) will provide upstream Coax Domain Nodefunctionality to optical fiber node (205) in that it will be able, inconjunction with Triplex unit 518 c, to intercept upstream RF signalssent by any communication devices (e.g. FIG. 4 209) attached to the CATVcable between the CDN-fiber node and the first true Coax Domain Node,and in combination with MUX-1 unit (500) and/or optionally transceiver(512) convert this local upstream data to optical wavelengths forupstream transmission over optical fiber (218).

Note that often one or more of these components will run under thesoftware control of one or more microprocessors (not shown), so thattheir characteristics may be remotely adjusted by commands sent from thecable head end, or from the Coax Domain Nodes (e.g. a request for anadditional channel) as desired.

FIG. 5A also shows a diagram of the Coax Domain Node(s) (272). Thesenodes, which generally interrupt the CATV coax cable (226, 270) atvarious intervals (e.g. are junctions in the CATV cable based tree andbranch network), perform a number of functions. On the CATV cable facingthe downstream portions of the cable (226 d, 270 d—the cable branch,away from the cable head and the fiber node), there will often be atriplex/filter unit (530), and there will also generally be anothertriplex filter unit (532) at the upstream (226 u, 270 u —facing thecable head and the fiber node) portion of the Cable Domain Node.Upstream signals from the cable head are processed by the add dropmultiplexer (ADM) repeater (534), and those signals intended fortransmission on the lower frequency range (e.g. 5-865 MHz) (540) aresent to the RF synthesizer (536). Additionally, 1 GHz+ wideband upstreamsignals intended for downstream or upstream transmission (542) are alsohandled by ADM repeater (534) and triplex/filter (530). Finally, lowfrequency upstream signals (e.g. 5-42 MHz region), (544) often sent byvarious households connected to the domain controlled by that particularCoax Domain Node are processed by processor (538), sent to ADM repeater(534), where they can be converted to 1 GHz+ RF signals and sent backupstream in the direction of the fiber node (205) and the cable headend. These lower frequency upstream signals are shown in more detail inFIG. 9.

The ADM repeater essentially handles RF signal traffic on the 1 GHz+wideband frequencies. This unit both merges new data in the form of new1 GHz+ signals onto the 1 GHz+ wideband pathway (270), and alsointelligently (i.e. usually under microprocessor or microcontrollercontrol) extracts the relevant data from the 1 GHz+ wideband frequencies(270).

The various Cable Domain Nodes (272) will often have at least one andoften more than one of their components (e.g. 534, 536, 538) andoptional tunable triplex units (530, 532) run under the software controlof one or more microprocessors/microcontrollers (not shown), so thattheir characteristics may be remotely adjusted by commands sent from thecable head end, or from the CDN-Fiber Node, or from other Coax DomainNodes (e.g. a request for an additional channel) as desired. TheCDN-Fiber node (205) will also similarly be adjustable under softwarecontrol, and can often also accept remote commands. Generally it iscontemplated that the flexible upstream and downstream frequencyallocation schemes shown in FIG. 8 and FIG. 9 will be accomplished bysuch software control methods.

In some embodiments, to improve data handling capability still further,it may be useful to extract the underling digital data from the variouscable RF waveforms, and repackage this underlying digital data into amore efficient format. To do this, the various devices (205), (272) maybe further given the capability to do this type of intelligent dataextraction and repackaging. One way is by MAP data analysis, describedbelow.

FIG. 5B shows a block diagram that focuses on a second alternativeembodiment of the optical fiber node (CDN-fiber node) (205 a) and onescheme in which this optical fiber node can interact with acomplementary embodiment of the cable head end (202 a). In thisembodiment, the head end (202 a) can be transmitting various forms ofmultiservices data (212) such as standard definition TV (SD), highdefinition TV (HD) SDV, video on demand (VOD), internet protocoltelevision (IPTV), high speed data (HSD), passive optical network (PON)data, voice over IP (VOIP) and the like. In this scheme, the head endcan send and receive data from the various CDN-fiber nodes (205 a) to(212) by digital modulators and electrical to optical converters (570)and optical wavelength multiplexers (501 a) (500 b) and demultiplexers(501 b) (500 a). Additionally, through the use of A/D converters (563),and electrical to optical converters and digital modulators (564), thesystem can also carry downstream legacy CATV signals (566). Similarly,through the use of suitable optical demultiplexers (501 b), optical toelectrical converters (501 b), digital demodulators (574) and digital toanalog converters (574), the head end can also handle upstream legacyCATV signals as well.

In this scheme, the head end (202 a) transmits the downstream opticalfiber signals at various wavelengths λ_(f1) . . . λ_(fn) (f beingforward here) to this particular implementation of a CDN-fiber node (205a) along optical fiber (218 a). The head end (202 a) in turn receivesupstream optical fiber signals at various wavelengths λ_(r1) . . .λ_(rn) from the CDN-fiber node (205 a) along optical fiber (218 b).

In this scheme, once at the CDN-fiber node (205 a), the downstreamoptical fiber signals (218 a) are first demultiplexed using opticaldemultiplexer (500 a) into three types of signals. One type, handled bydigital demodulator and optical to electrical signal converter (550) isintended for CATV RF transmission at 1 GHz+ frequencies to the variousupstream Coax Domain Nodes (272). This is handled by transceiver (512)and sent to the portion (518 a) of the triplex unit (518) that handles 1GHz+ signals, and this data is transmitted upstream to the various CDNunits (272) along the wideband communications pathway (270 u).

In this scheme, some of the downstream optical fiber signals intendedfor transmission to any local domain households (e.g. 209) on, forexample, the 54-865 MHz RF frequency band can also be extracted fromdemultiplexer (500 a), handled by digital demodulator and optical toelectrical converter (552), converted to suitable analog waveforms byD/A converter (553) and merged with any other locally generated RFsignals generated by CMRTS QAM Edge module (514 a) (to be discussed).These merged signals are then sent to the roughly (54-865 MHz) arm (518b) of triplex (518).

Alternatively or additionally, often some or all of the local domainCATV RF signals in the roughly 54-865 MHz region may be generated by the<1 GHz RF signal synthesizer (514), here represented as the CMRTS QAMEdge module synthesizer/receiver (514 a).

In some embodiments, the triplex unit (518) can be adjusted to not block(e.g. pass) some signals in the 54-865 MHz region (e.g. have anarrowpass filter). In these schemes, then broadcast signals being sentdownstream or forward to multiple domains can pass through path (552),(553), (568), while more domain specific narrowcast signals can gothrough path (556), (554), (514 a). However it should be appreciatedthat this scheme is quite flexible, and alternative broadcast/narrowcastallocation schemes may also be used.

Upstream signals, here assumed to be local domain upstream signals inthe roughly 5-42 MHz upstream RF frequency sent by local domain devices(209), can be split off by triplex (518) along arm (518 c), and eithersent to QAM edge module (514 a) for signal extraction and upstreamtransmission along path (558) to optical multiplexer (500 b).Alternatively some or all of the local domain upstream signals can besimply converted by A/D converter (560), modulated to digital signals bydigital modulator and electrical to optical converter (562), againhandled by optical multiplexer (500 b), and sent upstream as opticalsignals at various wavelengths along optical fiber (218 b).

Often however, the upstream signals from more distant domains will betraveling as 1 GHz+ CATV RF signals along wideband communicationspathway (270 u). As a result, these upstream signals will often besegregated by triplex (518) along arm (518 a) and travel back totransceiver (512). Transceiver (512) can then handle these 1 GHz+upstream signals along path (513) and again send them upstream by(handled or not by digital modulator and electrical to optical converter(562) according to the design of transceiver design (512), by opticalmultiplexer (500 b) along optical fiber path (218 b).

FIG. 5C shows a block diagram that focuses on a third alternativeembodiment of the optical fiber node (CDN-fiber node) (205 b) and onescheme in which this optical fiber node can interact with acomplementary embodiment of the cable head end (202 b). In thisembodiment, as well, the head end can again be transmitting variousforms of data (212) (e.g. multiservices) such as standard definition TV(SD), high definition TV (HD) SDV, video on demand (VOD), internetprotocol television (IPTV), high speed data (HSD), passive opticalnetwork (PON) data, voice over IP (VOIP) and the like. In thisparticular scheme as well, the head end can send and receive data fromthe various CDN-fiber nodes (205 b) to (212) using digital modulatorsand optical to electrical, electrical to optical converters (570) andoptical wavelength multiplexers (501 a) (500 b) and demultiplexers (501b), (500 a).

Here, instead of using a digital modulator (564) and analog to digitalconverter (563) as was previously discussed in FIG. 5B, in FIG. 5C,downstream legacy CATV signals (566) are instead handled by analogmodulators and electrical to optical converters (564 a), by way ofoptical multiplexer (501 a) and fiber (218 a).

Similarly, through the use of suitable digital demodulators and opticalto electrical converters (574), as well as optical demultiplexer (501 b)and fiber (218 b), and digital to analog converters (576), the head end(202 b) can also handle upstream legacy CATV signals (577) as well.

In this particular scheme, the head end (202 b) also transmits thedownstream optical fiber signals at various wavelengths λ_(f1) . . .λ_(fn) to this particular implementation of a CDN-fiber node (205 b)along optical fiber (218 a). The head end (202 b) receives upstreamoptical fiber signals at various wavelengths λ_(r1) . . . λ_(rn) fromthe CDN-fiber node (205 b) along optical fiber (218 b).

In this scheme, once at the CDN-fiber node (205 b), the downstreamoptical fiber signals (218 a) are again first demultiplexed usingoptical demultiplexer (500 a) into three types of signals. One type,handled by digital demodulator and optical to electrical converter (550)is intended for wideband CATV RF transmission at 1 GHz+ frequencies, andthis is handled by transceiver (512) and sent to the portion (518 a) ofthe triplex unit (518) that handles 1 GHz+ signals, and this data is asbefore transmitted upstream to the various CDN units (272) along thewideband communications pathway (270 u).

In this scheme, some of the downstream optical fiber signals intendedfor transmission to any local domain households (e.g. 209) on, forexample, the 54-865 MHz RF frequency band can also be extracted fromoptical demultiplexer (500 a), but instead of the previous schemediscussed in FIG. 5B, here in the FIG. 5C scheme, these signals areinstead handled by analog demodulator and optical to electricalconverter (552 a) and again merged with any locally generated RF signalsgenerated by CMRTS QAM Edge module (514 a), and sent to the roughly(54-865 MHz) arm (518 b) of triplex (518).

As before, alternatively or additionally, often some or all of the localdomain upstream CATV RF signals in the roughly 54-865 MHz region may begenerated by the <1 GHz RF signal synthesizer (514), here again in theform of synthesizer/receiver CMRTS QAM Edge module (514 a).

As before, in some schemes, the triplex unit (518) can be adjusted tonot block (e.g. pass) some signals in the 54-865 MHz region (e.g. have anarrowpass filter). In these schemes, then broadcast signals being sentdownstream or forward to multiple domains can pass through path (552 a),(568), while more domain specific narrowcast signals can go through path(556), (554), (514 a). However it should be appreciated that as before,this scheme is quite flexible, and alternative broadcast/narrowcastallocation schemes may also be used.

As before, upstream signals, here assumed to be local domain upstreamsignals in the roughly 5-42 MHz upstream RF frequency such as those sentby local domain devices (209) can be split off by triplex (518) alongarm (518 c), and either sent to QAM edge module (514 a) for signalextraction and upstream transmission along path (558) to opticalmultiplexer (500 b). Alternatively some or all of the local domainupstream signals can again be simply converted by A/D converter (560),modulated to digital signals by digital modulator and electrical tooptical converter (562), again handled by optical multiplexer (500 b),and sent upstream as optical signals at various wavelengths alongoptical fiber (218 b).

As before, often however, the upstream signals from more distant domainswill be traveling as 1 GHz+ CATV RF signals along widebandcommunications pathway (270 u). As a result, these upstream signals willbe segregated by triplex (518) along arm (518 a) and travel back totransceiver (512). Transceiver (512) can then handle these 1 GHz+upstream signals along path (513) and again send them upstream by(handled or not by digital modulator (562) according to the transceiverdesign (512), by optical multiplexer (500 b) along optical fiber path(218 b).

FIG. 5D shows a block diagram that focuses on a fourth alternativeembodiment of the optical fiber node (CDN-fiber node) (205 c) and onescheme in which this optical fiber node can interact with acomplementary embodiment of the cable head end (202 c). In thisembodiment, as well, the head end can again be transmitting variousforms of data (212) (e.g. multiservices), again such as standarddefinition TV (SD), high definition TV (HD) SDV, video on demand (VOD),internet protocol television (IPTV), high speed data (HSD), passiveoptical network (PON) data, voice over IP (VOIP) and the like., herethrough switch (580). In this particular scheme as well, the head endcan send and receive data from the various CDN-fiber nodes (205 c) bydigital modulators and electrical to optical converters (564 b) andelectronic digital multiplexers (501 c), (500 d) and demultiplexers (500c) (501 d).

In FIG. 5D, downstream legacy CATV signals (566) are instead handled byanalog to digital converters (563) and sent to electronic multiplexer(501 c), and the electrical signals are then transduced to opticalsignals by digital modulator and electrical to optical converter (564b).

Similarly, through the use of suitable digital demodulators and opticalto electrical converters (574 b), as well as digital electronicdemultiplexer (501 d) and fiber (218 b), the head end (202 c) can alsohandle upstream legacy CATV signals (577) as well.

In this particular scheme, the head end (202 c) transmits the downstreamoptical fiber signals at various wavelengths λ_(f1) . . . λ_(fn) to thisparticular implementation of a CDN-fiber node (205 c) along opticalfiber (218 a). The head end (202 c) receives upstream optical fibersignals at various wavelengths λ_(r1) . . . λ_(rn) from the CDN-fibernode (205 c) along optical fiber (218 b).

In this scheme, once at the CDN-fiber node (205 c), the downstreamoptical fiber signals (218 a) are first converted from optical todigital electronic signals by digital demodulator and optical toelectrical converter (565 a) and demultiplexed using digital electronicdemultiplexer (500 c) into three types of signals again. As before, onesignal is intended for wideband CATV RF transmission at 1 GHz+frequencies, and this is again handled by transceiver (512) and sent tothe portion (518 a) of the triplex unit (518) that handles 1 GHz+signals, and this data is as before transmitted upstream to the variousCDN units (272) along the wideband communications pathway (270 u).

In this scheme, as before, some of the downstream optical fiber signalsintended for transmission to any local domain households (e.g. 209) on,for example, the 54-865 MHz RF frequency band can also be extracted fromdemultiplexer (500 c), but instead of the previous schemes, here in theFIG. 5C scheme, these are handled by digital to analog converter (553)and again merged with any locally generated RF signals generated byCMRTS QAM Edge module (514 b), and sent to the roughly (54-865 MHz) arm(518 b) of triplex (518).

As before, alternatively or additionally, often some or all of the localdomain CATV RF signals in the roughly 54-865 MHz region may be generatedby the <1 GHz RF signal synthesizer (514), here in the form ofsynthesizer/receiver CMRTS QAM Edge module (514 b).

As before, in some schemes, the triplex unit (518) can be adjusted tonot block (e.g. pass) some signals in the 54-865 MHz region (e.g. have anarrowpass filter). In these schemes, broadcast signals being sentdownstream or forward to multiple domains can pass through the path thatgoes through (553), (568), while more domain specific narrowcast signalscan go through path (556 a) and (514 b) to (518 b). However it should beappreciated that as before, this scheme is quite flexible, andalternative broadcast/narrowcast allocation schemes may also be used.

As before, upstream signals, here assumed to be local domain upstreamsignals in the roughly 5-42 MHz upstream RF frequency sent by localdomain devices (209) can be split off by triplex (518) along arm (518c), and either sent to QAM edge module (514 b) for signal extraction andupstream transmission along path (558 a) to digital electronicmultiplexer (500 d) and from there to digital modulator and electricalto optical converter 562 a. Alternatively some or all of the localdomain upstream signals can be digitized by A/D converter (560), handledby digital electronic multiplexer (500 d), digitally modulated tooptical signals by digital modulator and electrical to optical converter(562 a), and sent upstream as optical signals at various wavelengthsalong optical fiber (218 b).

As before, often however, the upstream signals from more distant domainswill be traveling as 1 GHz+ CATV RF signals along widebandcommunications pathway (270 u). As a result, these upstream signals willbe segregated by triplex (518) along arm (518 a) and travel back totransceiver (512). Transceiver (512) can then handle these 1 GHz+upstream signals along path (513) and again send them upstream by(handled or not by digital modulator (562 a) according to thetransceiver design (512), by multiplexer (500 d) along optical fiberpath (218 b).

FIG. 6 shows an overview of how Mini-slot Allocation Packet (MAP) data(600), (602) may be used to analyze and extract the digital data encodedby the upstream signals (604). This process of analysis and digital dataextraction may be done at different locations, such as at the CoaxDomain Nodes (272), or alternatively (particularly if the Coax DomainNodes simply pass along all upstream data without processing) at or nearthe CDN-fiber node (205). This step can be performed by a processor orDSP (606) that receives the upstream data, and uses the MAP data (602)to understand the timing and assignment of the various time slices usedto convey the upstream data from the various cable modems at the variousneighborhood households.

The upstream digital data may then be sent back to the cable head andthe Cable Modem Termination System (CMTS) (216) at the cable head usinga more efficient digital protocol, such as a GigE protocol, along theHFC optical fiber (218). At the CMTS end (216) as desired, the same MAPdata (608) (610) may be used, in conjunction with the digital data (andpossibly in decoder apparatus (400)) to reconstitute the originalupstream CATV RF signal at a remodulator (612). This reconstitutedupstream signal may in turn be fed into the CMTS (216), which may be alegacy CMTS, as desired. This helps leverage the cable industry'sconsiderable investment in standard DOCSIS equipment, and helps reducethe costs and effort involved in providing additional functionality tothe system's various users. Alternatively, when more advanced CMTSsystems that are designed to directly interpret the upstream data areused, remodulation step (612) may be omitted.

Map extraction may be done by various methods. Since the CMTS processorgenerates MAP data, one of the simplest methods is simply to modify theCMTS processor software to send out (downstream) an easy to interpretform of the MAP data for use by the system, and communicate this MAPdata down optical fiber (218) to the processor (606) that will beanalyzing the neighborhood upstream data. Alternatively, less directmethods, such as sniffing methods discussed in Azenko and Rakib, U.S.Pat. No. 7,362,773 (incorporated herein by reference) may be used. Ingeneral, a broad range of alternative MAP extraction methods may be usedfor the invention. Often, however, it will be useful to extract the MAPdata at the cable head end, and transmit this MAP data to the opticalnodes (205) and Coax Domain Nodes (272) at the CATV RF side of thesystem.

As one alternative MAP scheme, the MAP data may not be used fordemodulating the upstream data at all, but rather simply be used to maskor “clean up” the upstream data. Here for example, the RF bursts sentout by various cable modems during times that the MAP data has allocatedfor that particular cable modem's upstream transmission time can simplybe passed on as is (i.e. as a pure analog to analog pass through), whileduring the “dead” times when the MAP data indicates that a particularcable modem or set of cable modems is not allocated time to transmit, nosignal may be passed on. Thus upstream RF transmissions during timeperiods or windows when upstream transmission by the cable modemsattached to a particular Coax Domain Node are not authorized may bemasked. Here the net effect of this alternative scheme is to reduce theoverall upstream noise, while preserving the upstream data. This sort ofscheme can be useful in reducing interference that may be caused, forexample, by inadvertent crosstalk between cable modems that are servedby an alternative Coax Domain Node, but through which some signals haveinadvertently leaked to a region of the CATV cable served by a differentCoax Domain Node.

FIG. 7 shows one wideband communications pathway and Coax Domain Nodeaddressing scheme. Here either each Coax Domain Node, or in someembodiments related groups of Coax Domain Nodes are partitioned intodifferent domains (700), (702), (704), (708), and the cable modems inthe various households (e.g. 208) served by their respective Coax DomainNodes (272) are addressed by the cable plant or head end CMTSaccordingly. In one simple scheme, the various communication devices(e.g. household cable modems) falling within each Coax Domain Nodedomain are handled by the CMTS as if they were simply small independentneighborhoods, thus partitioning what is really a larger CATV coaxneighborhood into multiple virtual smaller neighborhoods. This schemehelps preserve backward compatibility with legacy CMTS and CMTSsoftware.

Here the addressing model used by CMTS (214) is shown as (710). Althoughthe various domains (700, 702, 704, 708) served by the neighborhood CATVcable served by Fiber Node or CDN-Fiber node (205) are actually part ofthe same CATV coax system, for purposes of at least handling theupstream data, the addressing scheme used by the CMTS (710) can treatthese various domains (700, 702, 704, 708) as if they were simply smallindependent neighborhood CATV cables, each connecting to the CMTS bytheir own respective slots (712, 714, 718). This scheme helps preservelegacy CMTS hardware and software, as well as other legacy cable headsystems. Alternative domain addressing schemes may also be used.

Thus here, the CATV trunk cable or branch CATV cables, and the variousCoax Domain Nodes can be addressed as multiple domains, so that one setof cable devices (such as cable modems) attached the CATV trunk andbranch cable arrangement that is local to and served by a first CoaxDomain Node (e.g. 720) may be addressed on a first domain basis (e.g.domain 704), and other sets of cable devices attached to said at leastone CATV trunk cable or at least some of said plurality of branch CATVcables that is local to and serviced by a second Coax Domain Node (e.g.272) may be addressed on a second domain basis (e.g. domain 700).

Although often it will be convenient to designate each group ofhouseholds served by a particular Coax Domain Node as having its ownunique address or CMTS slot, in alternative embodiments, as desired,multiple domains may be combined and addressed as a unit. Thus forexample in an alternative scheme, domains (700) and (704) might beaddressed as a single “virtual neighborhood CATV cable” by the CMTS(214, 710), while domains (702) and (708) might be addressed as adifferent “virtual neighborhood CATV cable” by the CMTS (214, 710).Although potentially limiting the upstream data rate capability, suchdomain pooling arrangements may be useful for simplifying addressingschemes, preserving compatibility with legacy CMTS and other equipmentwhich may have a limited number of available slots or neighborhoodports, and for other purposes as well.

In at least some embodiments, it may be useful to endow the Coax DomainNode with at least one processor and software that enables the CoaxDomain Node to keep track of exactly which communication devices arewithin the sphere of coverage or domain of that particular Coax DomainNode. This simplifies management and control of the system.

FIG. 8 shows one scheme in which the Coax Domain Nodes may allocatefrequency and payloads among the various coax cable domains.

In this example, by virtue of the fact that the various Coax DomainNodes (CDN₁, CDN₂, CDN₃) generally only pass the high frequencies (e.g.1 GHz+, or at least above the upstream frequencies of 5-42/88 MHz, theCoax Doman Nodes end up segmenting the CATV coax into various domains,here called Coax₁, Coax₂, and Coax₃, and so on. Particularly in the casewhere the Coax Domain Nodes are set to filter various bandwidths of RFsignals below about 1 GHz, then as can be seen in the frequency map(800), the RF signals in each domain can be different.

In this example, the Coax Domain Nodes (272) are configured aspreviously shown in FIG. 5A, and have triplex units such as (530) and(532). These triplex units only allow frequencies above about 1 GHz topass (816) (boosted, relayed, or modified as appropriate by the add dropmultiplexer ADM repeater (534)). The triplex units intercept andterminate all signals from about 0-5 MHz to about 865 MHz-1 GHz.

Thus, within each domain Coax1, Coax2, Coax3, both the standard CATVupstream RF signals from about 5-54 or 88 MHz (810) are isolated fromthe other domains, and the standard CATV downstream RF signals (812),(814) are isolated from the other domains. Only the 1 GHz+ frequencies(816) pass between domains in a relatively free manner. (Note in somealternative schemes, certain “notch” frequencies less than 1 GHz mayalso be allowed to freely pass or be relayed as desired).

With this scheme, then within the Coax₁ domain, the frequency allocation(802) is such that the upstream RF signals (originating from variouscommunications devices connected to Coax₁) from say 0-54/88 MHz (US₁)are confined to the Coax₁ domain. Similarly the upstream signals in theother Coax₂ and Coax₃ domains (804), (806) are also confined to theirdomains because they are terminated by the respective Coax Domain NodesCDN₁, CDN₂, and CDN₃. Thus each upstream channel US₁, US₂, and US₃ inthis scheme is unique. The only way that the upstream data can make itback to the CDN-fiber node (205) and hence to the cable head end is ifthe various Coax Domain Nodes repackage it and upconvert it to a higherfrequency such as the 1 GHz+ frequency (816).

The various Coax Domain Nodes can be set to extract the same set of data(e.g. channels) from the 1 GHz+ wideband pathway (270), and send this asthe same general broadcast channels BCH (812) across all domains (e.g.802, 804, 806). Alternatively the Coax Domain Nodes can be set toextract different types of data (e.g. different channels) from the 1GHz+ wideband pathway (270), and narrowcast this (814) to differentselected domains. This can be done by, for example, sending theappropriate commands to the ADM repeater (534) and <1 GHz RF signalsynthesizer (536) to extract the appropriate data and QAM modulate orother modulate and transmit downstream as desired.

Thus the only way that there will be RF signals and data on thesefrequencies (e.g. the 54/88 MHz to about 865 to 1 GHz range) is if thevarious Coax Domain Nodes select data that is passed along (e.g. 1 GHz+wideband frequencies (816), and using their RF signal synthesizers (536)create signals in these wavelength bands (812), (814), and inject thisinto their various domains.

The narrowcast signals (814) generated at that particular CDN node canbe of various types. For example, they can include data, voice or videoover IP data addressed to a household in that particular domain for thevarious domains (NC_(N,1), NC_(N,2), and NC_(N,3)).

As previously discussed, in the 1 GHz+ wideband frequency range (816),data intended to flow freely across domains is transmitted. This datacan consist of the intra node payload, and can be transmitted in variousformats such as 2-Way frequency division (2-Way-FD), Time divisionduplex (TDD), Frequency division duplex (FDD), and other formats asdesired.

FIG. 9 shows a detail of one scheme in which the Coax Domain Nodes mayallocate upstream frequencies and payloads among the various coax cabledomains. Note that in this scheme, because the different domains areisolated from each other in the downstream frequency region (e.g. 5-42MHz or 5-88 MHz) (810) these frequency and time slices need not beconsistent between the different domains, even though the domains allfall at various locations along the CATV cable. Thus for example, Settop boxes STB₁, STB₂, STB₃ can all transmit upstream at the same timeand frequency, as well as Cable Modems CM_(1,1), CM_(2,1), CM_(3,1),CM_(2,1), CM_(2,2), CM_(3,3), CM_(3,1), CM_(3,2), and CM 3,3 withouthaving to compensate for devices transmitting upstream in the otherdomains. The net effect is to greatly reduce congestion and improveupstream communications speeds.

FIG. 10 shows a schematic of how the cable head end can, with the aid ofa suitable router, take various forms of data in IP space, such asanalog video, digital video, video on demand, as well as other signalsgenerated by the head end cable modem termination system (CMTS),modulate this to analog optical signals, add various types of narrowcastpayloads (in digital format), multiplex these, and transmit (andreceive) as various optical signals over the optical fiber to variousoptical fiber nodes.

FIG. 11 shows an alternative scheme of how the cable head end (e.g. 205)can, with the aid of a suitable router, take various forms of data in IPspace, such as analog video, digital video, video on demand, as well asother signals generated by the head end cable modem termination system(CMTS), modulate this to analog optical signals, add various types ofnarrowcast payloads (in digital format), multiplex these, and transmit(and receive) as various optical signals over the optical fiber tovarious optical fiber nodes. In this alternative scheme, the narrowcastsignals (narrowcast payload) can be sent using presently unused opticalfibers (e.g. dark fiber).

The invention claimed is:
 1. A method for enhancing data carryingcapacity of a hybrid fiber cable (HFC) network with a cable head end, atleast one optical fiber, at least one optical fiber node terminating onat least one cable television (CATV) cable, said CATV cable connected toa plurality of branch CATV cables thus forming a CATV Tree and BranchNetwork, and a plurality of communication devices connected to said CATVTree and Branch Network, said method comprising: creating abidirectional wideband communications pathway mediated by radiofrequencies (RF) of approximately 1 GHz or greater between said at leastone optical fiber node and to and between a plurality of Coax DomainNodes disposed along said CATV Tree and Branch network; wherein saidCoax Domain Nodes are junctions in said CATV Tree and Branch network,and pass CATV RF signals of approximately 1 GHz frequency or more, butintercept and terminate at least some CATV RF signals of approximately 1GHz frequency or less; at least some of said plurality of Coax DomainNodes also communicating with their own set of local CATV cableconnected communications devices on a local domain specific basis; usingsaid Coax Domain Nodes to A: intercept local upstream CATV RF signalsfrom said communications devices, said local upstream CATV RF signalshaving a frequency of approximately 1 GHz or less, B: terminate at leastsome of said local upstream CATV RF signals; C: modulate either saidlocal upstream CATV RF signals or data obtained from said local upstreamCATV RF signals to an RF frequency of approximately 1 GHz or more; D:and backhaul either said local upstream CATV RF signals or data obtainedfrom said local upstream CATV RF signals to said at least one opticalfiber node using said wideband communications pathway; and E: using saidCoax Domain Nodes and data obtained from said wideband communicationspathway, to transmit domain specific downstream data to said local CATVcable connected communications devices by modulating and transmitting atleast selected portions of said data obtained from said widebandcommunications pathway using downstream CATV RF signals of approximately1 GHz or less.
 2. The method of claim 1, wherein said upstream CATV RFsignals of approximately 1 GHz frequency or less comprise signalsselected from the group consisting of Data Over Cable Service InterfaceSpecification (DOCSIS), Digital Video Broadcasting (DVB), Aloha, andother non-DOCSIS signals, and wherein at least some of said DOCSISsignals are terminated by said Coax Domain Nodes and backhauled usingsaid wideband communications pathway.
 3. The method of claim 1, whereinall of said upstream CATV RF signals of approximately 1 GHz frequency orless are terminated by said Coax Domain Nodes and backhauled using saidwideband communications pathway.
 4. The method of claim 1, wherein saidwideband communications pathway comprises CATV cable, CATV cableconnectors and/or active devices capable of passing through frequenciesof 1 GHz and higher, and amplifiers capable of overcoming theattenuation of RF frequencies of approximately 1 GHz or greater as afunction of CATV cable distance.
 5. The method of claim 4, wherein saidwideband communications pathway, when said Coax Domain Nodes arebypassed, is further capable of passing through at least some RFfrequencies between 5 to 865 MHz.
 6. The method of claim 1, wherein saidCoax Domain Nodes operate by the steps of: 1: digitizing at least someof said upstream CATV RF signals of approximately 1 GHz frequency orless; 2: modulating at least some of the digitized upstream CATV RFsignals to RF frequencies of approximately 1 GHz or greater, creatingwideband communications pathway signals.
 7. The method of claim 6,wherein the steps of digitizing said upstream CATV RF signals ofapproximately 1 GHz frequency or less are done by the steps of: A:obtaining Mini-slot Allocation Packet (MAP) data for at least some ofsaid upstream CATV RF signals; B: using said Mini-slot Allocation Packet(MAP) data to demodulate and extract at least some of the upstreamdigital information carried by at least some of said upstream CATV RFsignals; C: repackaging said upstream digital information in analternative format for transmission using RF frequencies ofapproximately 1 GHz or greater; and D: transmitting said upstreamdigital information in said alternative format using said Widebandcommunications pathway.
 8. The method of claim 7, further using saidMini-slot Allocation Packet (MAP) data to subsequently remodulate saidupstream digital information into reconstituted upstream CATV RF signalsat said cable head, producing reconstituted upstream CATV RF signals;and supplying said reconstituted upstream CATV RF signals to a CableModem Termination System.
 9. The method of claim 1, wherein downstreamdata is transmitted over said optical fiber from said Cable head end tosaid optical fiber node at a first wavelength, and said upstream data istransmitted from said optical fiber node to said head end over saidoptical fiber at a second wavelength.
 10. The method of claim 1, furtherusing said wideband communications pathway and said Coax Domain Nodes totransmit either upstream or downstream wideband communication pathwaydata according to a Time Division Duplex (TDD) scheme, FrequencyDivision Duplex (FDD) scheme, or Full Bidirectional Duplex without timeor frequency division scheme.
 11. The method of claim 1, wherein atleast some of said Coax Domain Nodes contain at least one QuadratureAmplitude Modulated (QAM) modulator device capable of encoding, on adomain specific basis, selected portions of said downstream widebandcommunications pathway data into RF QAM waveforms; and whereinmodulating at least selected portions of said downstream widebandcommunications pathway data into downstream CATV RF signals ofapproximately 1 GHz frequency or less at said Coax Domain Nodes is doneusing said at least one QAM modulator device.
 12. The method of claim 1,wherein said Coax Domain Nodes further comprise: at least one QuadratureAmplitude Modulated (QAM) modulator device capable of encoding selectedportions of digitally encoded wideband communications pathway data intoRF QAM waveforms of approximately 1 GHz frequency or less; at least onesoftware controllable switch that can be remotely directed to select, ona domain addressable basis, at least some of said digitally encodedWideband communications pathway data and direct said at least one QAMmodulator device to encode said selected digitally encoded ultrahighfrequency CATV RF communications data into RF QAM waveforms ofapproximately 1 GHz frequency or less at a selected set of frequencieswithin each said domain; at least one remotely software controllable RFpacket processor capable of detecting upstream data carried by CATV RFupstream signals waveforms of approximately 1 GHz frequency or lessgenerated by communications device(s) within each domain, and digitallyrepackaging said upstream data and retransmitting said upstream dataalong said wideband communications pathway; wherein said at least onesoftware controllable switch and/or said software controllable RF packetprocessor are capable of being remotely configured by software to assignor reassign, on a domain specific basis, the frequencies used by saidupstream data and/or downstream data being carried by RF QAM waveformsof approximately 1 GHz frequency or less.
 13. A method for enhancing thedata carrying capacity of a hybrid fiber cable (HFC) network with acable head end, at least one optical fiber, at least one optical fibernode terminating on at least one cable television (CATV) cable, saidCATV cable connected to a plurality of branch CATV cables thus forming aCATV Tree and Branch Network, and a plurality of communication devicesconnected to said CATV Tree and Branch Network, said method comprising:creating a bidirectional wideband communications pathway mediated byradio frequencies (RF) of approximately 1 GHz or greater between said atleast one optical fiber node and to and between a plurality of CoaxDomain Nodes disposed along said CATV Tree and Branch network; whereinsaid Coax Domain Nodes are junctions in said CATV Tree and Branchnetwork, and pass CATV RF signals of approximately 1 GHz frequency ormore, but intercept and terminate at least some CATV RF signals ofapproximately 1 GHz frequency or less; at least some of said pluralityof Coax Domain Nodes also communicating with their own set of local CATVcable connected communications devices on a local domain specific basis;using said Coax Domain Nodes to A: intercept local upstream CATV RFsignals from said communications devices, said local upstream CATV RFsignals having a frequency of approximately 1 GHz or less; B: terminateat least some of said local upstream CATV RF signals; C: modulate eithersaid local upstream CATV RF signals or data obtained from said localupstream CATV RF signals to an RF frequency of approximately 1 GHz ormore; D: and backhaul either said local upstream CATV RF signals or dataobtained from said local upstream CATV RF signals to said at least oneoptical fiber node using said wideband communications pathway; and E:using said Coax Domain Nodes, and data obtained from said widebandcommunications pathway, to transmit domain specific downstream data tosaid local CATV cable connected communications devices by modulating andtransmitting at least selected portions of said data obtained from saidwideband communications pathway using downstream CATV RF signals ofapproximately 1 GHz or less; wherein said Coax Domain Nodes modulatesaid local upstream CATV RF signals by the steps of: a) digitizing atleast some of said upstream CATV RF signals of approximately 1 GHzfrequency or less; b) modulating at least some of the digitized upstreamCATV RF signals to RF frequencies of approximately 1 GHz or greater,creating wideband communications pathway signals; wherein at least someof said Coax Domain Nodes contain at least one Quadrature AmplitudeModulated (QAM) modulator device capable of encoding, on a domainspecific basis, selected portions of said downstream widebandcommunications pathway data into RF QAM waveforms; and whereinmodulating at least selected portions of said downstream widebandcommunications pathway data into downstream CATV RF signals ofapproximately 1 GHz frequency or less at said Coax Domain Nodes is doneusing said at least one QAM modulator device.
 14. The method of claim13, wherein said wideband communications pathway comprises CATV cable,CATV cable connectors and/or active devices capable of passing throughfrequencies of 1 GHz and higher, and amplifiers capable of overcomingthe attenuation of RF frequencies of approximately 1 GHz or greater as afunction of CATV cable distance; and wherein said widebandcommunications pathway, when said Coax Domain Nodes are bypassed, isfurther capable of passing through at least some RF frequencies between5 to 865 MHz.
 15. The method of claim 13, wherein said upstream CATV RFsignals of approximately 1 GHz frequency or less comprise signalsselected from the group consisting of Data Over Cable Service InterfaceSpecification (DOCSIS), Digital Video Broadcasting (DVB), Aloha, andother non-DOCSIS signals, and wherein at least some of said DOCSISsignals are terminated by said Coax Domain Nodes and backhauled usingsaid wideband communications pathway.
 16. The method of claim 13,wherein said Coax Domain Nodes further comprise: at least one QAMmodulator device capable of encoding selected portions of digitallyencoded downstream wideband communications pathway data into RF QAMwaveforms of approximately 1 GHz frequency or less; at least onesoftware controllable switch that can be remotely directed to select, ona domain addressable basis, at least some of said digitally encodeddownstream wideband communications pathway data and direct said at leastone QAM modulator device to encode said selected digitally encodeddownstream wideband communications pathway data into downstream RF QAMwaveforms of approximately 1 GHz frequency or less at a selected set offrequencies within each said domain; at least one remotely softwarecontrollable RF packet processor capable of detecting upstream datacarried by CATV RF upstream signals waveforms of approximately 1 GHzfrequency or less generated by communications device(s) within eachdomain, and digitally repackaging said upstream data and retransmittingsaid upstream data along said wideband communications pathway; whereinsaid at least one software controllable switch and/or said softwarecontrollable RF packet processor are capable of being remotelyconfigured by software to assign or reassign, on a domain specificbasis, the frequencies used by said upstream data and/or downstream databeing carried by RF QAM waveforms of approximately 1 GHz frequency orless.
 17. The method of claim 16, further remotely directing saidsoftware controllable switch to select, on a plurality of Coax DomainNodes on said CATV Tree and Branch Network, a broadcast portion of saiddigitally encoded downstream wideband communications pathway data anddirect the said at least one QAM modular device on each of saidplurality of Coax Domain Nodes to encode said broadcast portion intobroadcast RF QAM waveforms of approximately 1 GHz frequency or less foreach of said plurality of Coax Domain Nodes.
 18. The method of claim 16,further remotely directing said software controllable switch to select,on one or more selected Coax Domain Nodes on said CATV Tree and BranchNetwork, a narrowcast portion of said digitally encoded downstreamwideband communications pathway data and direct the said at least oneQAM modular device on each of said selected Coax Domain Nodes to encodesaid narrowcast portion into narrowcast downstream RF QAM waveforms ofapproximately 1 GHz frequency or less for each of said selected CoaxDomain Nodes; Wherein said Coax Domain Nodes intercept and terminatesaid narrowcast downstream RF QAM waveforms at said junctions in saidCATV Tree and Branch network, thus preventing said narrowcast downstreamRF QAM waveforms from being transmitted beyond said junctions.